Tachometer.



PATEN'IED JULY 11, 1905.

e. SAALBR. TAGHOMETER.

APPLICATION FILED NOV. 29, 1904. 1

UNirno STATES Patented July 11, 1905.

PATENT @FFICIE...

GUSTAV SAALER, OF EMMENDINGEN, GERMANY, ASSIGNOR TO NIAGARA TAOHOMETER- AND INSTRUMENT COMPANY, OF NIAGARA FALLS, NEWV YORK, A CORPORATION OF NEW YORK.

TACHOIVIETER.

SPECIFICATIONforming part of Letters Patent No. 794,426, dated July 11, 1905.

Application filed November 29, 1904:. Serial No. 234,737.

To all whom, it may concern:

Be it known that I, GUsTAv SAALER, a subject of the German Emperor, residing at Emmendingen, Grand Duchy of Baden, Germany,

have invented certain new and useful Improvements in Tachometers; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it ap- IO pertains to make and use the same.

My invention relates to an improvement in rotary speed-indicators of the same general.

class as described in an application heretofore filed on November 14, 1904.

I5 My present invention is a modification thereof; and it consists in a construction by which the range of indication is much extended.

The essential features are two separated substantially equal containers for the mercury arranged at equal distances from the vertical axis of rotation. Each container is connected by a very small hole to a cylindrical rising chamber, the holes being at the extreme outer edge of both container and rising chamber.

2 5 Each rising chamber is connected at its upper end by a gradually-diminishing connectingtube to the vertical axially-arranged indicating-tube. A return-tube connected to the indicating-tube at its top extends to about the 0 foot of the latter and is connected by branches to the two containers. The containers are nearly filled with mercury, and the rising chambers, connecting tubes, and branches with a lighter liquid preferably to about or a little above the foot of the indicating-tube. Here the proportions are also important, but different from those of the device of my said application. In the invention here described the total capacity of the rising chambers 4 should be at least equal (a slight excess is not objectionable) to the capacity of the indicating portion of the indicating-tube; but the containers are of such size that the total mercury therein contained is substantially double the 4.5 total contents of both the rising chambers. By this proportion and by the fact that there is no large connection filled with mercury between the containers, which central bulk of mercury would tend by its weight to force the mercury adjacent to the holes outwardly, and so upwardly, there is less force applied to the mercury during rotation, and it rises much more slowly and gradually in the rising chambers and permits a wider range of inclication from the lowest indicated speed to about four times that speed (one to four) for instance, about from three hundred to twelve hundred or, as indicated, about from two hundred to eight hundred revolutions per minute.

It will be understood that for most rotating 6o objects such as shafts, turbines, dynamos, centrifugal separators, &c. the bestand most economical speed for each particular machine or location is approximately known, and therefore it is not generally necessary to measure or indicate any wide range of speeds; but where indicators for a wide range are desired my present device is practical and well adapted.

My invention will be understood by reference to the drawings herewith, in which the 7 reference-numerals of the specification indicate the same parts in all the figures.

Figure I is a front elevation of my indicator or indicating vessel withan illustrative scale arranged adjacent to the indicating-tube. 7 5 Fig. II is a side elevation. Figs. III and IV are cross-sections of Fig. I on lines III and IV, respectively. Fig. V shows a slight modification in form. Figs. VI. and VII are respectively vertical and cross sections of an electrical alarm which may be used with my speed-indicator of any construction.

In the figures, 1 1 indicate the two containers, preferably circular in cross-section with flat tops and in general form a short cylinder with 5 a hemispherical base, like the end of a testtube. Their depth is about equal to their diameter. They are equal in size, as near as may be, and arranged parallel and correspondingly at equal distances from the axis. 9

2 2 are small holes connecting the respec tive containers to their rising chambers 3 3 and arranged at the extreme outer margins of boththat is, at the greatest distance from the axis of rotation. From one millimeter to about two millimeters, as near as may be, are

desirable sizes for the holes. If they are substantially above three millimeters in diameter, they would be too large and there would be danger of the lighter liquid flowing back during rotation. They are as small as can reasonably be made; but it will be understood that where the indicating vessel is blown from glass very slight variations cannot be avoided. I

The preferably cylindrical rising chambers are united by connecting-tubes 5 5 to the foot of the indicating-tube 6, connecting at its upper end with the preferably larger returntube 8, from whose lower end extend the large branch tubes 9 9 to the tops of the respective containers for the return of the lighter liquid accidentally overflowing. Each branch should be at least substantially as large in diameter as the indicating-tube.

The containers are nearly filled with mercury, leaving only a small space for the lighter liquid (preferably tinted) to connect the holes with the branches, so that the lighter liquid accidentally overflowing may flow back into the containers when the indicator is at rest. This lighter liquid stands about at a level in the tubes about at the foot of the indicatingtube and a short distance below the foot of the scale, it being preferred that the scale should not extend to the foot of the indicating-tube, but leave a little space in which the lighter liquid will rise before it begins to indicate. On account of capillarity the lighter liquid may stand a little higher initially in the indicating-tube than in the return-tube. The scale may be stationary and inclosed in the outer glass tube 17 or in some cases inscribed directly on the return -tube, where that incloses the indicating-tube.

It will be understood that the indicating vessel here described and shown in Figs. I to V may be made of glass in one piece and may be inclosed in a shell and mounted in a case provided with means for connecting it to the rotating object, all as described in my former application. The only difference in the de vice of Fig. V is that the branch is extended as a single tube down'to or nearly to the level of the container, where it divides, and therefore its upper portion must be of larger capacity.

The electrical alarm (shown in Figs. VI and VII) may be applied to any similar tachometer. It consists of a cap 30, of insulating material, secured on the indicating-tube and having abearing 21 in cap 19 on outer glass tube 17, which is part of the case in which the indicator is inclosed. This cap 30 is provided with an axial chamber 31 and outer chambers 32 32, connected above and below and containing mercury or other electrically-conducting liquid of an amount proportioned to the speed at which the alarm is to be given. Chambers 32 should be equal and at equal distances from the center.

33 is alower metallic band in constant connection by plugs with the mercury, and 34 is an upper band, also having plugs which enter the outer chambers and make connection with the mercury when it is raised along the outer sides of the outer chambers by a sufficient centrifugal force, then closing the circuit and giving the alarm that an undesirable speed has been reached.

37 and 38 are spring-contacts fixed in cap 19 and respectively in contact with bands 33'and 34:. Here cap 19 must be of insulating material or the spring-contacts be insulated therefrom, as by suitable bushings. The contacts are connected by wires to bell or other suitable alarm, which is sounded when the circuit is closed by the rise of the mercury into con tact with the plugs of upper band 34:.

The chambers in the cap are preferably small, that the mercury may move up and down uniformly and gradually. If the chambers were large, the mercury would tend to be forced up rapidly and fall slowly, which would cause inaccuracy in the alarm.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is

1. As a new article of manufacture, an indicating vessel for a tachometer, said vessel being adapted to be rotated on a vertical axis and having in combination two containers, a rising chamber connected to each container, an indicating-tube connected to the rising chambers, and return connections from the upper portion of the indicating-tube to the containers.

2. .As a new article of manufacture, an indicating vessel for a tachometer, said vessel being adapted to be rotated on a vertical axis and having in combination two similar containers, a rising chamber connected to each container, an indicating-tube connected to the rising chambers, and return connections from the upper end of the indicating-tube to the upper portions of the containers, the capacity of each containerbeing not substantially less than twice the capacity of each rising chamher.

3. In a tachometer, a closed indicating vessel made entirely of glass and adapted to rotate on a vertical axis, said vessel having in combination a plurality of similar, separated containers, of uniform size and uniformly arranged at substantially equal distances from tube inclosing the indicating-tube, a branch connecting the foot of the return-tube with the tops of the respective containers, mercury nearly filling each container, and a lighter liquid resting on the mercury and filling the vessel about to the foot of the indicating-tube, the total capacity of the rising chambers being not substantially less than the capacity of theindicating-tube and each container being of about twice the capacity of each rising chamber.

4. As a new article of manufacture, a glass indicating vessel for a tachometer, having in combination a plurality of substantially equal containers, symmetrically arranged with reference to the axis of rotation, a rising chamber connected to each container, an indicatingtube connected to the rising chambers and return connections from the upper end of the indicating-tube to the containers.

5. A glass indicating vessel for a tachometer having in combination aplurality of substantially equal containers, a rising chamber connected to each container, a single indicatingtube connected at its lower end to the upper ends of all the rising chambers, return connections from the upper end of the indicatingtube to the containers, mercury nearly filling the containers and a lighter liquid above the mercury filling the vessel about to the foot of the indicating-tube, the containers being of such a size that the amount of mercury therein contained shall not be less than twice the capacity of all the rising chambers, and not 'less than twice the capacity of the indicatingtube.

6. A glass indicating vessel for a tachometer, having in combination two equal containers, in the form of short cylinders, vertically arranged, having substantially semiglobular bases, a rising chamber on each container and connected thereto by asmall hole, an indicatin g-tube connected to the rising chambers and return connections from the upper end of the indicating-tube to the containers.

7. A one-piece, closed, glass indicating vessel for a tachometer, adapted to be rotated on a vertical axis, and having in combination two substantially equal containers, symmetrically arranged with reference to the axis, each container being in the form of a vertically-arranged, short cylinder having substantially a semiglobular base, a cylindrical rising chamber on each container and connected thereto by a small hole, an indicating-tube arranged above the rising chambers and having its lower end connected to the upper ends of said chambers, and return connections from the upper end of the indicating-tube to the tops of the containers, the rising chambers being substantially equal in total capacity to the indicatingtube and the total capacity of the containers being substantially double the capacity of all the rising chambers.

8. In a tachometer, a glass indicating vessel adapted to be rotated on its vertical axis and having in combination containers symmetrically arranged with reference to the axis, rising chambers arranged on the containers and connected therewith by holes arranged adjacent to the outer walls, said holes being not less than one millimeter and not substantially more than three millimeters in diameter, an indicating-tube, having an open upper end, arranged in the axis of rotation and connected to the upper ends of the rising chambers, a return-tube extending from the open upper end of the indicating-tube down adjacent to the lower end of the indicating-tube, a branch connecting the lower portion of the returntube with the upper portion of the containers, mercury nearly filling the containers, and a lighter liquid resting on the mercury and filling'the various parts of the vessel about to the foot of the indicating-tube substantially as described and shown.

In testimony whereof I afiix my signature in presence of two witnesses.

GUSTAV SAALER. Witnesses:

F. W. GAERTNER, M. B. SMITH. 

